The present invention relates to chucks for a machine tool and more particularly to scroll chucks for a machine tool.
As well-known in the art scroll chucks for a machine tool, e.g. lathe, have such defects that the force of the claws constituting the chuck to clamp a workpiece is weak and the constitutional components to actuate the claws are easily subject to wear, making the cntering of the workpiece difficult.
As a countermeasure, to compensate for the defects of the scroll chucks, hydroulic chucks have also been well-known in the art. However, they reveal another defect that since each time the diameter of a workpiece changes, the claws have to be shifted by loosening the bolts fastening them to the main body in order to adapt them to the changed diamter, taking a long time to rechuck the workpiece, etc.